The witches squeaked in shock when the plane's motors first began to spin, filling the air with the distinctive sound of propellers. Cassie was gently maneuvering the plane to the end of the runway so that they had as much room as possible to get over the trees and wouldn't have to give away all the secrets of their aircraft on the first flight.
It could raise up nearly vertically with Air Magic, but that was hard on the power reserves, and it would encourage the Witches in the Swamps to think that they could land on a tiny strip in the middle of nowhere.
Pretending that it took a hundred metres or more to get properly airborne would give the proper attitude toward flight and encourage them to meet here, where there was infrastructure in place and solid ground for the plane to land on.